Aleromod.com - View Single Post - How To: Retrofit an autodimming rear view mirror with compass and temperature readout

wws944 · 12-31-2012, 02:08 PM

A few more comments:

First, sunroof cars already have a map light. So +12v, switched ground (to allow the BCM to turn the map lights on when a door is opened), and ground are already available. For cars that don't have this, the same wires are available at the dome light. This then leaves the temp sensor wire (for mirrors with temp display) and reverse signal (for mirrors with auto-dim) to run down the A pillar.

Looking at the wiring diagram in the Haynes #38026 manual, page 12-37, there is a mistake or two. It only shows two connections to the mirror - +12v and ground. In my '04 at least, the mirror is also connected to the switched ground - as the dome light is. Is this a change from earlier cars?

As an aside, I also note that the wiring diagram also shows a right (passenger) vanity mirror light. My car does not have one - even though it is a 'loaded' GLS. It only has a non-lit drivers side vanity mirror. Was that also a change from earlier cars? (Or perhaps a Malibu or Cutlass had it?)

12-31-2012, 02:08 PM	#18
wws944 GX Member Join Date: Aug 2012 Location: Northern California Posts: 57	A few more comments: First, sunroof cars already have a map light. So +12v, switched ground (to allow the BCM to turn the map lights on when a door is opened), and ground are already available. For cars that don't have this, the same wires are available at the dome light. This then leaves the temp sensor wire (for mirrors with temp display) and reverse signal (for mirrors with auto-dim) to run down the A pillar. Looking at the wiring diagram in the Haynes #38026 manual, page 12-37, there is a mistake or two. It only shows two connections to the mirror - +12v and ground. In my '04 at least, the mirror is also connected to the switched ground - as the dome light is. Is this a change from earlier cars? As an aside, I also note that the wiring diagram also shows a right (passenger) vanity mirror light. My car does not have one - even though it is a 'loaded' GLS. It only has a non-lit drivers side vanity mirror. Was that also a change from earlier cars? (Or perhaps a Malibu or Cutlass had it?) __________________ 2004 Alero GLS (and a few others)